Number

43

43 is a prime, odd, a calendar year.

Arithmetic Number Cousin Prime Deficient Number Evil Number Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Historical context — 43 AD

Calendar year

AD 43 (XLIII) was a common year starting on Tuesday of the Julian calendar.

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Historical context — 43 BC

Calendar year

Year 43 BC was either a common year starting on Sunday, Monday or Tuesday or a leap year starting on Sunday or Monday of the Julian calendar and a common year starting on Monday of the Proleptic Julian calendar.

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Year facts

Year type: Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
Days in year: 365
ISO weeks: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 43
Ended on: Thursday
December 31, 43
Friday the 13ths: 3
3 Friday the 13ths this year.
Decade: 40s
40–49
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 1,983
1983 years before 2026.

In other calendars

Hebrew: 3803 / 3804 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Water zodiac:Rabbit
Sexagenary cycle position 40 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 586 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 35 / 36 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -35 / -36 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 2
Digit sum: 7
Digit product: 12
Digital root: 7
Palindrome: No
Bit width: 6 bits
Reversed: 34
Recamán's sequence: a(18) = 43
Square (n²): 1,849
Cube (n³): 79,507
Divisor count: 2
σ(n) — sum of divisors: 44
φ(n) — Euler's totient: 42

Primality

43 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 43

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 43)

1 × 43

First multiples

43 · 86 (double) · 129 · 172 · 215 · 258 · 301 · 344 · 387 · 430

Sums & aliquot sequence

As consecutive integers: 21 + 22

Representations

In words: forty-three
Ordinal: 43rd
Roman numeral: XLIII
Binary: 101011
Octal: 53
Hexadecimal: 0x2B
Base64: Kw==
One's complement: 212 (8-bit)

In other bases

ternary (3) 1121

quaternary (4) 223

quinary (5) 133

senary (6) 111

septenary (7) 61

nonary (9) 47

undecimal (11) 3a

duodecimal (12) 37

tridecimal (13) 34

tetradecimal (14) 31

pentadecimal (15) 2d

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓎆𓎆𓏺𓏺𓏺
Greek (Milesian): μγʹ
Mayan (base 20): 𝋢·𝋣
Chinese: 四十三
Chinese (financial): 肆拾參

In other modern scripts

Eastern Arabic ٤٣ Devanagari ४३ Bengali ৪৩ Tamil ௪௩ Thai ๔๓ Tibetan ༤༣ Khmer ៤៣ Lao ໔໓ Burmese ၄၃

Digit at this position in famous constants

π — Pi (π): Digit 43 = 9
e — Euler's number (e): Digit 43 = 7
φ — Golden ratio (φ): Digit 43 = 9
√2 — Pythagoras's (√2): Digit 43 = 1
ln 2 — Natural log of 2: Digit 43 = 0
γ — Euler-Mascheroni (γ): Digit 43 = 9

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 41 (gap of 2)
Next prime: 47 (gap of 4)

Pair status: twin with 41, cousin with 47.

ASCII character

As an ASCII codepoint, 43 is +. Printable ASCII character +.

Hex color

#00002B

RGB(0, 0, 43)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.43.

Address: 0.0.0.43
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.43

Unspecified address (0.0.0.0/8) — "this network" placeholder.

US numbered highway

Matches numbered highway designation:

I-43 — Beloit to Green Bay, WI.

Interstate 43 on Wikipedia ↗